Multiple solutions for critical Choquard-Kirchhoff type equations

AbstractIn this article, we investigate multiplicity results for Choquard-Kirchhoff type equations, with Hardy-Littlewood-Sobolev critical exponents,−a+b∫RN|∇u|2dxΔu=αk(x)|u|q−2u+β∫RN|u(y)|2μ∗|x−y|μdy|u|2μ∗−2u,x∈RN,$$\begin{array}{} \displaystyle -\left(a + b\int\limits_{\mathbb{R}^N} |\nabla u|^2 dx\right){\it\Delta} u = \alpha k(x)|u|^{q-2}u + \beta\left(\,\,\displaystyle\int\limits_{\mathbb{R}^N}\frac{|u(y)|^{2^*_{\mu}}}{|x-y|^{\mu}}dy\right)|u|^{2^*_{\mu}-2}u, \quad x \in \mathbb{R}^N, \end{array}$$wherea> 0,b≥ 0, 0 <μ<N,N≥ 3,αandβare positive real parameters,2μ∗=(2N−μ)/(N−2)$\begin{array}{} 2^*_{\mu} = (2N-\mu)/(N-2) \end{array}$is the critical exponent in the sense of Hardy-Littlewood-Sobolev inequality,k∈Lr(ℝN), withr= 2∗/(2∗−q) if 1 <q< 2*andr= ∞ ifq≥ 2∗. According to the different range ofq, we discuss the multiplicity of solutions to the above equation, using variational methods under suitable conditions. In order to overcome the lack of compactness, we appeal to the concentration compactness principle in the Choquard-type setting